You may know that cigarette smoking is the leading cause of preventable disease and death in the US, but did you know that smoking is also the number one preventable risk factor for bladder cancer? The good news is that fewer people are now smoking, and reducing exposure to tobacco smoke – as an active smoker or through secondhand sources – decreases bladder cancer risk and improves outcomes for those diagnosed with the disease.
- Can smoking cause bladder cancer?
- Smoking and bladder cancer: what is the risk?
- Can second-hand smoke cause cancer?
- How does smoking affect the bladder?
- Vaping versus smoking: does vaping cause cancer?
- Is vaping safer than smoking?
- Quitting smoking reduces cancer risk
- Looking to quit? Here’s where to get help
- Cxbladder testing can detect or rule out bladder cancer
Smoking causes cancer in at least 15 areas of the body, including the bladder.1 In the US, smoking causes around half of all bladder cancers in both men and women,2 making it the leading preventable risk factor, well ahead of workplace exposure to industrial chemicals.
The more you smoke, the higher the risk. Bladder cancer risk increases with smoking duration (the number of years you have smoked) and intensity (the number of cigarettes smoked each day), although duration appears to have a greater effect.3 Overall, smokers are at least three times more likely than non-smokers to develop bladder cancer. An analysis of data from multiple previously published studies (this is known as a meta-analysis) found that, relative to people who had never smoked, the risk of getting bladder cancer was 3.5 times higher for current smokers, improving to 2 times higher for former smokers (see bar graph).4 A second meta-analysis found a similar increase in bladder cancer risk for male and female smokers, but a higher risk in European compared with Asian populations.5 Some genetic variants are also linked to a higher increase in bladder cancer risk for smokers.6
Can second-hand smoke cause cancer?
Second-hand smoke (SHS), or involuntary smoking, exposes children, pets and non-smokers to the same carcinogens inhaled by smokers. There is no safe level, but home and workplace exposure are a particular concern, with a 20–30% increase in lung cancer risk for non-smokers exposed to SHS in these settings.7 While more research is needed to confirm potential links to other cancers, and results for bladder cancer have been inconsistent, a meta-analysis of 14 studies found that second-hand smoke exposure was linked to a 22% increase in bladder cancer risk.8 This is lower than the risk increase shown in the figure. It is reasonable to conclude that SHS significantly increases the risk of developing bladder cancer, although there is uncertainty over the precise level of risk.
Exposure to SHS can be measured by blood levels of cotinine, a chemical formed in the body after nicotine exposure. Linked to this, encouraging findings from the National Health and Nutrition Examination Survey (NHANES) show the percent of non-smokers exposed to SHS decreased from 88% in 1988 to 25% in 2014, but around two of every five children were still exposed to the harmful effects of SHS.9 Pets are also vulnerable! Dogs, cats and birds that live with smokers have an increased risk of cancer.10
In those who are diagnosed with bladder cancer, smoking leads to worse outcomes. Notably, being a smoker at the time of major bladder cancer surgery (cystectomy) increases the risk of serious complications, infections, and death after surgery.11 Smokers are also half as likely to respond to preoperative chemotherapy, more likely to have their bladder cancer return after surgery, and more likely to die of cancer.12
Cigarette smoke contains over 7,000 chemicals, including around 70 known to be cancer-causing agents (carcinogens).13 Some of the most damaging carcinogens in cigarette smoke include polycyclic aromatic hydrocarbons, nitrosamines, aromatic amines, 1,3-butadiene, benzene, aldehydes, and ethylene oxide.14 Two of the aromatic amines in cigarette smoke (2-naphthylamine and 4-aminobiphenyl) are a major cause of bladder cancer in smokers.14
So how does smoking cause cancer of the bladder? In its normal functioning, the body removes a variety of toxins through the urine. When you inhale, harmful chemicals in cigarette smoke are absorbed from the lungs into the blood before being filtered through the kidneys and collecting in the bladder. During the hours that urine sits in your bladder, the bladder lining is directly exposed to carcinogens. Some of these chemicals bind to and damage DNA, eventually leading to mutations and tumor formation, while others increase cancer risk indirectly, for example by harming the immune system and promoting inflammation.
Aside from causing cancer, smoking also irritates the bladder. Smoking can worsen symptoms of overactive bladder and interstitial cystitis (a chronic, painful bladder condition that is more common in women), such as urgent and frequent need to urinate. Coughing spasms can also provoke urine leakage in smokers. Other urologic conditions associated with smoking include kidney cancer, kidney stones, erectile dysfunction, and infertility.
Though vaping exposes the user to fewer toxic substances than smoking, it is not harmless: the aerosol inhaled and exhaled during vaping may contain nicotine, heavy metals, and carcinogens.15 Encouragingly the levels of carcinogens and toxins in e-cigarettes are much lower than in cigarettes, and short-term studies suggest that smokers who switch to vaping do experience reduced exposure to carcinogens.16 However, it is too soon to know the long-term risks, including whether vaping can cause cancer. Currently there are grounds for concern: 63 toxic or carcinogenic metabolite biomarkers have been identified in the urine of vapers, including several with a strong known link to bladder cancer.17
Clearly the healthy option is not to smoke or vape but, for adults who currently smoke cigarettes, switching to vaping is probably safer than smoking and may help with quitting completely. Combining vaping and cigarette smoking results in more potentially harmful chemicals being detected in the urine – it’s better to switch completely.18
Stopping smoking reduces the risk of many cancers over time. For bladder cancer, the risk drops steadily as the number of years since quitting smoking increases, with a definite reduction within 10 years.19 If this seems slow, remember that most cancers take many years to develop. Of course, quitting smoking has numerous additional health benefits, many of which occur rapidly, including a decrease in heart rate and blood pressure within 20 minutes and a reduction in carbon monoxide levels in the blood within hours, which increases the blood's ability to carry oxygen.20,21 Improved circulation and lung function (such as reduced phlegm, coughing and wheezing) can occur within a few weeks.
Due to the level of harm caused by smoking, quitting ultimately increases life expectancy by up to 10 years, depending on the age when you quit.20 Although the benefit is greater the earlier you stop, it’s never too late – quitting has many health benefits regardless of smoking duration, including if you’ve already been diagnosed with a smoking-related disease. In fact, a bladder cancer diagnosis can provide strong motivation, enabling smokers to successfully quit after decades of smoking.22
Looking to quit? Here’s where to get help
Though a range of factors may have influenced your decision to start and continue smoking, quitting is a personal decision – you must want to stop. Many people find it takes several attempts but do ultimately succeed, as can be seen in the declining rates of smoking in the US.23 Notably, quit rates do improve with support from others and specialized medication, so it’s worth trying different approaches to find what works for you. FDA-approved medications for stopping smoking include nicotine-replacement therapy (e.g., patches, gum and lozenges) and two prescription medications, varenicline and bupropion.
It's important to note that e-cigarettes (vaping) are not approved by the FDA for smoking cessation. Evidence from randomized trials does suggest that vaping with nicotine-containing e-cigarettes increases quit rates compared with nicotine replacement therapy.24 However, it’s not yet known whether people will continue vaping, or successfully quit nicotine altogether.
A range of useful and free online resources are available to help you clarify your own motivation to quit, make a plan, get tips to manage cravings, and recover from slip-ups. Recommended sites include Smokefree.gov and the Centers for Disease Control and Prevention (CDC) Tips From Former Smokers guide to How to quit smoking.
Activities to consider include:
- Build a quit plan
- Learn more about nicotine replacement therapy and smoking cessation and medications: fact vs fiction
- Get daily texts from SmokefreeTXT by texting QUIT to 47848. (This is a 6–8 week program for adults; additional text programs are available.)
- Try an app like QuitGuide and QuitSTART to identify your smoking patterns and triggers, then develop a customized quit plan
- Get quick answers about quitting smoking from the National Cancer Institute using live chat
Free and confidential phone helplines:
To get individualized advice and referrals from a trained counselor over the phone:
- 1-800-QUIT-NOW (1-800-784-8669) connects callers to a toll-free quit line in their home state
- NCI Smoking Quitline: 1–877–44U–QUIT (1–877–448–7848).
Resources for people living or working with smokers
Being exposed to the dangerous effects of second-hand smoke when it’s not your choice is a challenge. When it comes to family and friends, the American Cancer Society has tips on how to help someone quit smoking, but these do assume that the person is trying to quit. When this is not the case, two UK-based sites have advice:
- Action on Smoking and Health (ASH), Wales: What to do if you live with a smoker –conversations about quitting, practical tips (e.g., suggesting the person use nicotine replacements to manage cravings in the house).
- The Mix: How can I cope with living with smokers? While aimed at young people, many points are relevant to anyone living with a smoker who may have no intention of quitting.
Beyond the immediate household, SHS exposure is a particular problem in apartment complexes and assisted-living facilities, where smoke can permeate the building through hallways and even ventilation systems. The American Nonsmokers' Rights Foundation (ANRF) has information and resources that may be useful: Are You Exposed to Secondhand Smoke In Your Home?
Workplace exposure to SHS is now less common due to legislation in many states, as well as smoke-free workplace policies set by employers. If you are exposed to SHS at work, the non-profit Workplace Fairness has a Q&A on Smoking and the Workplace and the ANRF also covers this issue: Smokefree Workplaces Are Good For Health & Business.
If you’re a current or former smoker concerned about your risk of developing bladder cancer, early detection gives the best chance for successful treatment. Blood in the urine (hematuria) is the number one symptom to be aware of, although most patients with hematuria do not have cancer.
Cxbladder is a non-invasive, clinically proven, genomic urine test optimized for the detection and management of bladder cancer. The test combines clinical risk factors with gene expression markers to quickly and accurately detect the presence or absence of bladder cancer. Cxbladder can accurately rule out bladder cancer, reducing the need for further invasive tests.
To streamline the bladder cancer testing process, Cxbladder in-home sampling is available for patients in the US, giving the option to submit a urine sample from the comfort of home. If you’re worried about blood in urine, or any other symptom of bladder cancer, we recommend you speak to your doctor and see if Cxbladder in-home sampling is right for you.
- Cancer Research UK. How does smoking cause cancer? [reviewed: March 19, 2021].
- Freedman ND, et al. Association between smoking and risk of bladder cancer among men and women. JAMA. 2011;306(7):737-45. [PubMed]
- van Osch FHM, et al. Modeling the complex exposure history of smoking in predicting bladder cancer: a pooled analysis of 15 case-control studies. Epidemiology. 2019;30(3):458-465. [PubMed]
- Cumberbatch MG, et al. The role of tobacco smoke in bladder and kidney carcinogenesis: a comparison of exposures and meta-analysis of incidence and mortality risks. Eur Urol. 2016;70(3):458-66. [PubMed]
- van Osch FH, et al. Quantified relations between exposure to tobacco smoking and bladder cancer risk: a meta-analysis of 89 observational studies. Int J Epidemiol. 2016;45(3):857-70. [PubMed]
- Garcia-Closas M, et al. Common genetic polymorphisms modify the effect of smoking on absolute risk of bladder cancer. Cancer Res. 2013;73(7):2211-20. [PubMed]
- Office on Smoking and Health (US). The Health Consequences of Involuntary Exposure to Tobacco Smoke: A Report of the Surgeon General. Atlanta, GA: Centers for Disease Control and Prevention; 2006. 7. Cancer Among Adults from Exposure to Secondhand Smoke.
- Yan H, et al. Secondhand smoking increases bladder cancer risk in nonsmoking population: a meta-analysis. Cancer Manag Res. 2018;10:3781-3791. [PubMed]
- Tsai J, et al. Exposure to Secondhand Smoke Among Nonsmokers — United States, 1988-2014. MMWR Morb Mortal Wkly Rep. 2018;67(48):1342-1346.
- Food and Drug Administration (US). Be Smoke-free and Help Your Pets Live Longer, Healthier Lives [reviewed: April 1, 2021].
- Tellini R, et al. Impact of smoking habit on perioperative morbidity in patients treated with radical cystectomy for urothelial bladder cancer: a systematic review and meta-analysis. Eur Urol Oncol. 2021;4(4):580-593. [PubMed]
- Cacciamani GE, et al. Association between smoking exposure, neoadjuvant chemotherapy response and survival outcomes following radical cystectomy: systematic review and meta-analysis. J Urol. 2020;204(4):649-660. [PubMed]
- Centers for Disease Control and Prevention (US). A Report of The Surgeon General. How Tobacco Smoke Causes Disease. Fact Sheet. 2010.
- Centers for Disease Control and Prevention (US); National Center for Chronic Disease Prevention and Health Promotion (US); Office on Smoking and Health (US). How Tobacco Smoke Causes Disease: The Biology and Behavioral Basis for Smoking-Attributable Disease: A Report of the Surgeon General. Atlanta (GA): CDC; 2010. 5, Cancer.
- Centers for Disease Control and Prevention (US). About Electronic Cigarettes (E-Cigarettes) [reviewed: November 10, 2022].
- Hawk ET, Colbert Maresso K. E-Cigarettes: unstandardized, under-regulated, understudied, and unknown health and cancer risks. Cancer Res. 2019;79(24):6079-6083. [PubMed]
- Bjurlin MA, et al. Carcinogen biomarkers in the urine of electronic cigarette users and implications for the development of bladder cancer: a systematic review. Eur Urol Oncol. 2021;4(5):766-783. [PubMed]
- Goniewicz ML, et al. Comparison of nicotine and toxicant exposure in users of electronic cigarettes and combustible cigarettes. JAMA Netw Open. 2018;1(8):e185937. [PubMed]
- Department of Health and Human Services (US). Smoking Cessation. A Report of the Surgeon General. Atlanta, GA: U.S. Department of Health and Human Services, Centers for Disease Control and Prevention, National Center for Chronic Disease Prevention and Health Promotion, Office on Smoking and Health, 2020.
- American Cancer Society. Health Benefits of Quitting Smoking Over Time [reviewed: November 10, 2020].
- National Cancer Institute (US). Harms of Cigarette Smoking and Health Benefits of Quitting [reviewed: December 19, 2017].
- Bassett JC, et al. Prevalence and correlates of successful smoking cessation in bladder cancer survivors. Urology. 2021;153:236-243. [PubMed]
- Centers for Disease Control and Prevention (US). Current Cigarette Smoking Among Adults in the United States [reviewed: March 17, 2022].
- Hartmann-Boyce J, et al. Electronic cigarettes for smoking cessation. Cochrane Database Syst Rev. 2021;9(9):CD010216. [PubMed]
- Alberg AJ. How Does Smoking Increase Your Cancer Risk? An Expert Q&A [July 2021].
- American Cancer Society. Bladder Cancer Risk Factors [revised: January 30, 2019].
- Food and Drug Administration (US). Fact or Fiction: What to Know About Smoking Cessation and Medications [reviewed: March 28, 2019].
- Food and Drug Administration (US). Want to Quit Smoking? FDA-Approved and FDA-Cleared Cessation Products Can Help [reviewed: July 21, 2022].
- Mobley D, Baum N. Smoking: its impact on urologic health. Rev Urol. 2015;17(4):220-5. [PubMed]
- National Cancer Institute (US). Secondhand Smoke and Cancer [reviewed: December 4, 2018].
- Urology Care Foundation of the American Urological Association. 7 Urologic Conditions Impacted by Smoking [14 March, 2018].
- Urology Care Foundation of the American Urological Association. Smoking and Vaping's Impact on Urologic Health with Dr. Keith Kowalczyk [Urology Care Podcast, 12:11 min].